01 - Preheat oven to 425°F. Position the rack in the center of the oven.
02 - Pat the chicken breasts dry with paper towels. Season both sides evenly with salt, black pepper, smoked paprika, and dried oregano.
03 - Heat 1 tablespoon of olive oil in a large oven-safe skillet over medium-high heat. Sear the chicken breasts for 2 to 3 minutes per side until a golden crust forms, then transfer to a plate and set aside.
04 - Add the remaining tablespoon of olive oil to the same skillet. Toss in the sliced bell peppers, red onion, and minced garlic. Sauté for 4 to 5 minutes until the vegetables are slightly softened.
05 - Return the seared chicken breasts to the skillet, nestling them among the sautéed vegetables. Sprinkle with crushed red pepper flakes if desired.
06 - Transfer the skillet to the preheated oven. Roast for 15 to 18 minutes until the chicken is cooked through to an internal temperature of 165°F and the peppers are tender.
07 - Remove the skillet from the oven. Garnish with freshly chopped parsley and serve immediately while hot.